1. Field of the Invention
The present invention relates to a dispenser apparatus which drops paste onto a work specimen such as a substrate, etc.
2. Prior Art
Conventionally, in die bonding processes for manufacturing semiconductor devices, for example, paste is dropped by means of a dispenser onto the surface of the work specimen before the bonding of dies to the work specimen is executed via a die bonding tool.
In such a dispenser, the spacing between the nozzle and the work specimen and the speed at which the nozzle is raised following the dropping of the paste are changed in accordance with the viscosity of the paste and the amount of paste to be dispensed. If the spacing between the nozzle and the work specimen is not appropriate, the paste spreads unevenly and adheres to the circumference of the nozzle, which is undesirable. If the speed at which the nozzle is raised after the paste has been dropped is inappropriate, strings of paste pulled up by the nozzle will not be broken in an appropriate manner. Thus, the formation of the paste dispensed on the surface of the work specimen will be poor.
In the conventional dispensers described above, the rotation of a motor is transmitted to a cam shaft via a gear chain, and a syringe (with a nozzle attached thereto) is driven upward and downward by a cam provided on the cam shaft. Thus, the spacing between the nozzle and the work specimen is adjusted by raising and lowering a stopper such as a screw, etc. provided on the syringe holder, and adjustment is performed visually by an operator. Changes in the speed to raise the nozzle are accomplished by replacing the aforementioned cams and gear chain.
In the prior art described above, since the spacing between the nozzle and the work specimen is adjusted manually, the adjustment not only lacks accuracy but also takes a considerable amount of time. Furthermore, since the speed to raise the nozzle is changed by replacing cams and gears, the work efficiency tends to poor, and it is difficult to adjust the apparatus to an appropriate speed which breaks the strings of paste created when the nozzle is pulled up.